[PATCH 3/4] powerpc/pseries: Expose PLPKS config values, support additional fields

[Andrew Donnellan]

From: Nayna Jain <nayna at linux.ibm.com>

The plpks driver uses the H_PKS_GET_CONFIG hcall to retrieve configuration
and status information about the PKS from the hypervisor.

Update _plpks_get_config() to handle some additional fields. Add getter
functions to allow the PKS configuration information to be accessed from
other files.

While we're here, move the config struct in _plpks_get_config() off the
stack - it's getting large and we also need to make sure it doesn't cross
a page boundary.

Signed-off-by: Nayna Jain <nayna at linux.ibm.com>
[ajd: split patch, extend to support additional v3 API fields, minor fixes]
Co-developed-by: Andrew Donnellan <ajd at linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd at linux.ibm.com>
---
 arch/powerpc/platforms/pseries/plpks.c | 118 ++++++++++++++++++++++---
 arch/powerpc/platforms/pseries/plpks.h |  58 ++++++++++++
 2 files changed, 164 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c
index 8ccc91143370..c5ae00a8a968 100644
--- a/arch/powerpc/platforms/pseries/plpks.c
+++ b/arch/powerpc/platforms/pseries/plpks.c
@@ -38,8 +38,16 @@ static u8 *ospassword;
 static u16 ospasswordlength;
 
 // Retrieved with H_PKS_GET_CONFIG
+static u8 version;
+static u16 objoverhead;
 static u16 maxpwsize;
 static u16 maxobjsize;
+static s16 maxobjlabelsize;
+static u32 totalsize;
+static u32 usedspace;
+static u32 supportedpolicies;
+static u32 maxlargeobjectsize;
+static u64 signedupdatealgorithms;
 
 struct plpks_auth {
 	u8 version;
@@ -220,32 +228,118 @@ static struct label *construct_label(char *component, u8 varos, u8 *name,
 static int _plpks_get_config(void)
 {
 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
-	struct {
+	struct config {
 		u8 version;
 		u8 flags;
-		__be32 rsvd0;
+		__be16 rsvd0;
+		__be16 objoverhead;
 		__be16 maxpwsize;
 		__be16 maxobjlabelsize;
 		__be16 maxobjsize;
 		__be32 totalsize;
 		__be32 usedspace;
 		__be32 supportedpolicies;
-		__be64 rsvd1;
-	} __packed config;
+		__be32 maxlargeobjectsize;
+		__be64 signedupdatealgorithms;
+		u8 rsvd1[476];
+	} __packed *config;
 	size_t size;
-	int rc;
+	int rc = 0;
+
+	size = sizeof(*config);
+
+	// Config struct must not cross a page boundary. So long as the struct
+	// size is a power of 2, this should be fine as alignment is guaranteed
+	config = kzalloc(size, GFP_KERNEL);
+	if (!config) {
+		rc = -ENOMEM;
+		goto err;
+	}
 
-	size = sizeof(config);
+	rc = plpar_hcall(H_PKS_GET_CONFIG, retbuf, virt_to_phys(config), size);
 
-	rc = plpar_hcall(H_PKS_GET_CONFIG, retbuf, virt_to_phys(&config), size);
+	if (rc != H_SUCCESS) {
+		rc = pseries_status_to_err(rc);
+		goto err;
+	}
 
-	if (rc != H_SUCCESS)
-		return pseries_status_to_err(rc);
+	version = config->version;
+	objoverhead = be16_to_cpu(config->objoverhead);
+	maxpwsize = be16_to_cpu(config->maxpwsize);
+	maxobjsize = be16_to_cpu(config->maxobjsize);
+	maxobjlabelsize = be16_to_cpu(config->maxobjlabelsize) -
+			  MAX_LABEL_ATTR_SIZE;
+	maxobjlabelsize = maxobjlabelsize < 0 ? 0 : maxobjlabelsize;
+	totalsize = be32_to_cpu(config->totalsize);
+	usedspace = be32_to_cpu(config->usedspace);
+	supportedpolicies = be32_to_cpu(config->supportedpolicies);
+	maxlargeobjectsize = be32_to_cpu(config->maxlargeobjectsize);
+	signedupdatealgorithms = be64_to_cpu(config->signedupdatealgorithms);
+
+err:
+	kfree(config);
+	return rc;
+}
 
-	maxpwsize = be16_to_cpu(config.maxpwsize);
-	maxobjsize = be16_to_cpu(config.maxobjsize);
+u8 plpks_get_version(void)
+{
+	return version;
+}
+
+u16 plpks_get_objoverhead(void)
+{
+	return objoverhead;
+}
+
+u16 plpks_get_maxpwsize(void)
+{
+	return maxpwsize;
+}
+
+u16 plpks_get_maxobjectsize(void)
+{
+	return maxobjsize;
+}
+
+u16 plpks_get_maxobjectlabelsize(void)
+{
+	return maxobjlabelsize;
+}
+
+u32 plpks_get_totalsize(void)
+{
+	return totalsize;
+}
+
+u32 plpks_get_usedspace(void)
+{
+	return usedspace;
+}
+
+u32 plpks_get_supportedpolicies(void)
+{
+	return supportedpolicies;
+}
+
+u32 plpks_get_maxlargeobjectsize(void)
+{
+	return maxlargeobjectsize;
+}
+
+u64 plpks_get_signedupdatealgorithms(void)
+{
+	return signedupdatealgorithms;
+}
+
+bool plpks_is_available(void)
+{
+	int rc;
+
+	rc = _plpks_get_config();
+	if (rc)
+		return false;
 
-	return 0;
+	return true;
 }
 
 static int plpks_confirm_object_flushed(struct label *label,
diff --git a/arch/powerpc/platforms/pseries/plpks.h b/arch/powerpc/platforms/pseries/plpks.h
index 275ccd86bfb5..c89740796660 100644
--- a/arch/powerpc/platforms/pseries/plpks.h
+++ b/arch/powerpc/platforms/pseries/plpks.h
@@ -68,4 +68,62 @@ int plpks_read_fw_var(struct plpks_var *var);
  */
 int plpks_read_bootloader_var(struct plpks_var *var);
 
+/**
+ * Returns if PKS is available on this LPAR.
+ */
+bool plpks_is_available(void);
+
+/**
+ * Returns version of the Platform KeyStore.
+ */
+u8 plpks_get_version(void);
+
+/**
+ * Returns hypervisor storage overhead per object, not including the size of
+ * the object or label. Only valid for config version >= 2
+ */
+u16 plpks_get_objoverhead(void);
+
+/**
+ * Returns maximum password size. Must be >= 32 bytes
+ */
+u16 plpks_get_maxpwsize(void);
+
+/**
+ * Returns maximum object size supported by Platform KeyStore.
+ */
+u16 plpks_get_maxobjectsize(void);
+
+/**
+ * Returns maximum object label size supported by Platform KeyStore.
+ */
+u16 plpks_get_maxobjectlabelsize(void);
+
+/**
+ * Returns total size of the configured Platform KeyStore.
+ */
+u32 plpks_get_totalsize(void);
+
+/**
+ * Returns used space from the total size of the Platform KeyStore.
+ */
+u32 plpks_get_usedspace(void);
+
+/**
+ * Returns bitmask of policies supported by the hypervisor.
+ */
+u32 plpks_get_supportedpolicies(void);
+
+/**
+ * Returns maximum byte size of a single object supported by the hypervisor.
+ * Only valid for config version >= 3
+ */
+u32 plpks_get_maxlargeobjectsize(void);
+
+/**
+ * Returns bitmask of signature algorithms supported for signed updates.
+ * Only valid for config version >= 3
+ */
+u64 plpks_get_signedupdatealgorithms(void);
+
 #endif
-- 
2.38.1